<html>
    <head>
        <meta charset="utf-8">
        <title>内容过滤器示例</title>
        <script src="./js/jquery-3.6.0.min.js" type="text/javascript"></script>
        <script>
            $(document).ready(function(){
                $("td:empty").css("background","grey")
            });
        </script>
    </head>
    <body>
     <table id="employees" width="200" border="1">
     <tr><th>ID</th><th>姓名</th><th>性别</th><th>年龄</th><th>学历</th></tr>
     <tr>
         <td>001</td>
         <td>张三</td>
         <td>女</td>
         <td></td>
         <td>大专</td>
     </tr>
     <tr>
         <td>002</td>
         <td>李四</td>
         <td>男</td>
         <td>30</td>
         <td></td>
     </tr>
     <tr>
         <td>003</td>
         <td>王五</td>
         <td></td>
         <td>25</td>
         <td>本科</td>
     </tr>   
    </table>
</body>
</html>